Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 230838
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
338 AM CDT TUE SEP 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT TUE SEP 23 2014

TODAY-TONIGHT...SFC ANALYSIS SHOWS AN AREA OF HIGH PRES CENTERED
OVER THE CENTRAL OHIO VALLEY REGION WITH ITS WRN EXTENT STILL
COVERING THE UPR MISS RIVER VALLEY THIS MRNG. ALOFT...AN UPR LVL
RIDGE IS CENTERED JUST ABOUT OVER MN...XTNDG SWD OVER IA/MO. WITH
THIS RIDGE SLOWLY MOVING EWD OVER MN INTO WI AND THE SFC HIGH PRES
ALLOWING FOR DECENT RADIATIONAL COOLING CONDS OVER ERN PORTIONS OF
THE WFO MPX CWFA WITH CLEAR SKIES AND NEARLY CALM WINDS...THE
COOLEST READINGS WILL BE FELT OVER WRN WI. IN ADDITION...PATCHY FOG
IS ALSO BEING SEEN THIS MRNG WHEREAS THE MN PORTION OF THE CWFA WITH
WARMER TEMPS AND A MORE S-SW COMPONENT OF WINDS ARND 5 MPH WILL
REMAIN FREE FROM FOG DEVELOPMENT. ANY FOG WILL GRADUALLY BURN OFF
SHORTLY AFTER DAYBREAK...THEN ATTENTION TURNS TO A COMPACT ROTATING
UPR LEVEL LOW MAKING ITS WAY EWD OVER THE NRN PLAINS. WITH A DEEP
SLY FETCH AHEAD OF THIS UPR LOW BRINGING IN HIGHER LEVELS OF
MOISTURE TO BE WRAPPED INTO THIS SYSTEM...ENHANCED OMEGA LIFT AHEAD
OF THE LOW WILL BE RESPONSIBLE FOR CREATING ISOLD TO SCTD SHWRS OVER
WRN AND SRN PORTIONS OF THE CWFA BY MIDDAY TDA. THOUGH CLOUDS WILL
CERTAINLY BE ON THE INCRS FROM THE SW...THE LACK OF A SFC LOW OR
FRONT ALONG WITH DRIER LOWER LEVELS WILL MAKE LOW LEVEL LIFT AND
MOISTURE CONVERGENCE A MITIGATING FACTOR TO BETTER PRECIP COVERAGE
AND QPF AMOUNTS...BUT WITH BETTER MODEL AGREEMENT ON AT LEAST -SHRA
OVER SWRN PORTIONS OF THE CWFA TDA AND EVEN THRU TNGT...HAVE
MAINTAINED SLGT-LOW CHC POPS FOR THOSE PORTIONS OF THE CWFA. SINCE
THE UPR LVL LOW IS XPCTD TO RUN INTO THE DRIER UPR RIDGE...OPEN UP
TO A TROF AND LIFT N...PRECIP IS NOT XPCTD TO MAKE MUCH MORE
PROGRESS EWD THAN CENTRAL MN THRU TNGT SO HAVE BEEN ABLE TO LEAVE
MUCH OF ERN MN INTO WRN WI DRY THRU THIS PART OF THE FCST PERIOD.
EVEN THE TWIN CITIES /AND THE I-35 CORRIDOR AS A WHOLE/ MAY HAVE A
TOUGH TIME RECEIVING PRECIP THRU THIS SHORT-TERM PERIOD BUT CANNOT
BE RULED OUT COMPLETELY SO SOME SLGT CHC POPS ARE INCLUDED ALONG AND
E OF INTERSTATE 35. AS FOR TEMPERATURES...AFTER QUITE THE SPREAD IN
LOW TEMPS THIS MRNG...RANGING FROM THE LWR 40S IN WRN WI TO THE LWR
50S IN WRN MN...TEMPS WILL EVEN OUT FOR HIGHS THIS AFTN INTO THE LWR
70S UNDERNEATH AN EXPECTED DECENT COVERAGE OF CLOUDS...ALBEIT
MID-TO-HIGH LEVEL. MODEST WARM AIR ADVECTION TNGT WITH DEEP S-SW
FLOW AT THE SFC AND ALOFT ALONG WITH THE BLANKET OF CLOUD COVER WILL
SPELL MUCH WARMER TEMPS FOR OVERNIGHT TUE INTO WED. LOWS WED MRNG
WILL RANGE ARND 50 IN WRN WI TO NEAR 60 IN WRN MN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 322 AM CDT TUE SEP 23 2014

MAIN FORECAST ISSUES OF NOTE WERE THE CONTINUED POPS THROUGH
WEDNESDAY NIGHT...WHICH RESULTED IN COOLER TEMPERATURES ON
WEDNESDAY. ALSO...INCREASED TEMPS LATER IN THE WEAK ABOVE GUIDANCE
BASED ON THE MASS FIELDS.

AT THE START OF THE PERIOD LIGHT RAIN SHOWERS SHOULD BE ONGOING
ACROSS THE WESTERN HALF OF THE FORECAST AREA. HIRES MODELS DEPICT
THIS...AND FORECAST SOUNDINGS OFF THE NAM/GFS SHOW DEEPER
MOISTURE...STRONGER VERTICAL MOTION...AND THEREFORE GENERATE MORE
PRECIP. MID LEVEL CLOUDS WILL LIMIT THE AFTERNOON HEATING...SO
DECREASED TEMPS ON WEDNESDAY...ESPECIALLY IN WESTERN WI.

AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE HIGH PLAINS AS THIS
SYSTEM GETS SHEARED APART IN THE NORTHERN STREAM. A THERMAL RIDGE
WILL BUILD TO THE WEST...AND BY FRIDAY AFTERNOON H850 TEMPS WILL
BE ON THE ORDER OF 17-19C ALONG THE MINNESOTA/DAKOTA BORDER.
FORECAST SOUNDINGS SHOW CLEAR SKIES...AND ALTHOUGH THE SURFACE
WINDS INITIALLY START OUT SOUTHEAST...AFTERNOON MIXING GRADUALLY
TRANSFERS SOUTHWESTERLY WINDS THROUGHOUT THE BOUNDARY LAYER WHICH
WILL BE A FAVORABLE SETUP FOR WARM TEMPERATURES...ESPECIALLY ALONG
THE MINNESOTA RIVER VALLEY. THIS SETUP HAS THE POTENTIAL TO BRING
MID AND EVEN UPPER 80S ACROSS WESTERN MN BY THE END OF THE
WEEK...SO RAISED TEMPS ABOVE THE MODEL CONSENSUS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1027 PM CDT MON SEP 22 2014

WINDS REMAIN LIGHT AND VARIABLE OVERNIGHT...PARTICULARLY AT WEST
CENTRAL WI SITES /KRNH AND KEAU/ NEAR THE SURFACE RIDGE AXIS. KEPT
THE MENTION OF FOG AT WI SITES GIVEN SIMILAR CONDITIONS TO LAST
NIGHT AND DEWPOINTS AROUND 50 DEGREES THIS EVE. WESTERN SITES
WILL HAVE A CANOPY OF HIGH CLOUDS MOVING IN AND WINDS WILL BE A
FEW KNOTS STRONGER...SO FOG IS LESS OF A CONCERN THERE. BY 00Z
WEDNESDAY...MID LEVEL SATURATION OCCURS AT WESTERN SITES WITH A
BKN-OVC DECK CIRCA 5KFT EXPECTED ALONG WITH A FEW SHOWERS. SOUTH-
SOUTHEAST WINDS PREVAIL ON TUESDAY WITH GUSTS DEVELOPING AT KAXN
AND KSTC.

KMSP...
CLEAR SKIES OVERNIGHT WITH MID/HIGH CLOUDS INCREASING
THROUGHOUT THE DAY ON TUESDAY. STILL EXPECT PATCHY FOG IN NEARBY
VALLEYS BUT NOT AT THE SITE. SOUTH-SOUTHEAST WINDS AOB 10KTS THROUGH
TUESDAY.

/OUTLOOK FOR KMSP/
WED...VFR. MVFR CIGS PSBL OVERNIGHT. WINDS SSE 12-15G25 KTS.
THU...VFR. WINDS S 7-10 KTS.
FRI...VFR. WINDS SSE 5-10 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...JPC
LONG TERM...JRB
AVIATION...LS





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